Pigment.



ROBERT HOCHSTETTER, OF CINCINNATI, OHIO.

IPIGMENT.

No Drawing.

Specification of Letters Patent.

Patented Feb. 4, 1913.

Application filed July 9, 1910. Serial No. 571,201.

To all whom it may concern Be it known that 1, ROBERT HooHs'rnT'rnR, a citizen of the United States, and a resident of Mount Auburn, Cincinnati, in the county o n onmn no 1:2:4,

with the sodium salt of betaoxynaphthoic acid C H CH COOH 2:3,

in a distinctly acid solution. This produces the acid salt of paranitrotoluene-orthoazobetaoxynaphthoic acid which is practically insoluble in water and is the new pigment, that is to say, the pigment, directly.

As a specific example of the production of my improved pigment, I dissolve 15.2 parts of paranitroorthotoluidin in 27 parts of muriatic acid of 20 degrees B. by aid of heat, and then cool the solution to 32 F.- by means of ice. Add 7.5 parts sodium nitrite (NaNO and stir until completely diazotized. To this diazotized solution add 7 .parts of sodium acetate and 10 parts of acetic acid 56%. Dissolve 18.8 parts of betaoxynaphthoic acid in 5 parts of caustic soda, 80%, NaOH, by aid of heat. Then cool to 70 degrees F. To this solution add the diazotized solution described above, stirring constantly. This produces the pigment.

The pigment is of a beautiful redcolor with a strong bluish tone. It is soluble in concentrated sulfuric acid with brilliant bluish-red color and is precipitated in the form of bluish-red flakes from this solution by adding water.

. In case a color of less tinctorial strength is desired, the pigment may be produced on an inert base such as blanc fixe, barytes, china clay, or similar substance. In this case the inert base is first made into a smooth paste with water, and then added to the solution of the sodium salt or betaoxynaphthoic acid before adding the solution of diazotized paranitroorthotoluidin.

I claim as myinvention- 1. As a new article of manufacture the acid salt of paranitrotoluene-orthoazo-betaoxy-naphthoic acid the same being red. in color with a strong bluish tone and in the dry form being insoluble in water, but soluble in alcohol; dissolving in sulfuric acid with a bluish red tone, the addition of water producing a precipitation in the form of flakes; and being incapable of reduction with zinc and hydrochloric acid or with stannous chlorid'and hydrochloric acid.

2. The process of coupling diazotized paranitroorthotoluidin with an alkaline salt of betaoxynaphthoic acid in a distinctly acid solution.

3. As a new article of manufacture, the acid salt of paranitrotoluene-orthoazo-betaoXy-naphthoic acid, the same being practically insoluble in 'water, red in color with a strong bluish tone; and being soluble in concentrated sulfuric acid with brilliant bluish red color, bluish red flakes being precipitated from the solu ion upon the addition of water.

In testimony, that I, claim the foregoing asmy invention I aifix my signature in the presence of two witnesses, this seventh day of July A. D. 1910.

ROBERT HOOHSTETTER. Witnesses:

JAMES HAMILTON, J.B. HAWLEY. 

